Conventional coating systems such as those used for fabricating photoreceptors via dip coating can only accommodate substrates of a limited range of widths due to the importance of maintaining critical spacing between the outer dimension of the substrate and the inner dimension of the coating vessel. This critical distance generally must be maintained, especially when coating non-stable dispersions due to the occurrence of streaks and other associated coating defects. Thus, in conventional coating systems, substrates of different widths generally require their own vessels that are appropriately dimensioned. This limitation increases the cost of manufacturing since it may not be possible for the coating vessel to be re-used with a substrate of a different width.
Conventional coating systems are illustrated in Mistrater et al., U.S. Pat. No. 5,693,372 and Petropoulos et al., U.S. Pat. No. 5,725,667.
There is a need, addressed by the present invention, for a new coating system which minimizes or avoids the above discussed problem.
The present invention is accomplished in embodiments by providing a apparatus comprising:
(a) a vessel for a solution having a bottom end and an open top end, and defining a vertical axis perpendicular to the bottom end;
(b) an insert device having a bottom surface and a top surface and nested within the vessel, wherein the insert device defines a passageway dimensioned for a substrate which is parallel to the vertical axis and extending through the insert device, and wherein the insert device also defines at least one bypass channel extending through the insert to allow solution within the vessel to flow to the top surface of the insert device; and
(c) an overflow container positioned adjacent the vessel to catch solution runoff from the top surface of the insert device.
There is also provided in embodiments an apparatus comprising:
(a) a vessel for a solution having a bottom end and an open top end, and defining a vertical axis perpendicular to the bottom end;
(b) an insert device having a top surface and a bottom surface, including:
(i) a first insert nested within the vessel, wherein the first insert defines a passageway extending through the first insert and parallel to the vertical axis; and
(ii) a second insert nested within the passageway of the first insert, wherein the second insert defines a passageway dimensioned for a substrate which is parallel to the vertical axis and extending through the second insert, wherein there is at least one bypass channel extending through the insert device to allow solution within the vessel to flow to the top surface of the insert device; and
(c) an overflow container positioned adjacent the vessel to catch solution runoff from the top surface of the insert device.